The present invention relates generally to vehicle occupant protection systems, and more particularly to gas generators employed in occupant protection systems incorporating inflatable protection devices.
Gas generators for use in inflatable vehicle occupant safety systems are well-known in the field of vehicle safety systems. Typically, such gas generators comprise a housing defining a combustion chamber, with a first, booster charge and a main gas generating charge positioned in the housing. An igniter, or squib, is also positioned in the housing to ignite the booster charge. Upon a crash event, combustion of the booster charge is typically initiated by providing an electrical signal to the igniter. Ignition of the booster charge induces ignition of the main charge, thereby providing the bulk of the inflation gas used to inflate an associated inflatable safety device.
Isolating the booster charge from the main charge is known to improve the combustion and, consequently, the gas generation of the main charge. Thus, the booster charge is physically separated from the main gas generant charge by features incorporated into, or attached to, the housing structure. Foils, burst shims, and similar components may be used to form a fluid isolation barrier between the respective chambers and are ruptured by the creation of hot combustion gases upon activation of the booster charge. In addition, various inflator structures such as walls, cups, tubes, etc., may be used to form the structure necessary to fluidly isolate the respective charges and to impart sufficient structural integrity to the inflator to withstand the forces attendant to activation. Combustion of the booster charge bursts one or more of the barriers fluidly isolating the booster charge from the main charge. However, manufacturing of the structures needed to isolate the booster charge from the main charge requires significant manufacturing time and effort, and requires additional material.